1. Field of the Invention
The present invention relates to a light emitting diode (LED) and a method of fabricating the same, and more particularly, to an LED using a semiconductor nanowire as an emission device and a method of fabricating the same.
2. Description of the Related Art
Conventionally, III-V group or II-VI group compound semiconductor materials, for example, GaN, have been used for light emitting diodes (LEDs). However, fabrication process technology of III-V group and II-VI group compound semiconductor materials is not as developed as silicon(Si)-based fabrication process technology, and forming a P-N junction is considerably troublesome because it is difficult to dope III-V group and II-VI group compound semiconductor materials. Thus, fabrication of LEDs is costly and takes much time. Nevertheless, III-V group and II-VI group compound semiconductor materials are being commonly adopted for LEDs due to the fact that they have very large direct bandgaps.
Meanwhile, Si-based process technology and various Si doping techniques have already been developed. However, since Si has a characteristic of having a small indirect bandgap, it has been utilized for typical rectifier diodes, transistors, CMOS devices for circuits, and memories rather than for LEDs.
As a result of recent research, it was confirmed that at nanoscale level Si makes the transition to a direct bandgap. In particular, it was observed that as the diameter of Si nanowires decreases, their bandgaps gradually increase due to a quantum confinement effect. Thus, when the diameter of a Si nanowire is less than 10 nm, visible light may be emitted. Noticeably, when the diameter of a Si nanowire is approximately 1.5 nm, it is possible to emit blue light.
Conventionally, formation of Si nanowires has been performed using a bottom-up technique in which crystalline Si nanowires are grown on a substrate. However, according to the bottom-up technique, forming uniform nanowires is difficult and takes much time. Furthermore, it is quite difficult to combine the bottom-up technique with a typical semiconductor fabrication process known as a top-down technique.